On the other hand, either the finite nucleus or the infinite nucleonic matter is an outstanding many-body system [1]}. Their properties originate from different important aspects such as the complicated nucleon-nucleon interactions with momentum-, density-, spin- and isospin-dependence [2]}, the (ultra-) relativistic effects [3]}, [4]}, [5]} produced in heavy-ion reactions as well as from extremely astrophysical environments like those in neutron stars and/or around black holes [6]}, the finite-size effects due to the non-ideal parameters coming into the problem (e.g., the finite scattering length or the large but finite nucleon numbers in the nucleus), and also the dimensionality.
Almost all the existing treatments up to today for solving the nuclear many-body problems are done in 3 dimensions. However, there exist low-dimensional or quasi low-dimensional problems. For instance, a long time ago J. Wheeler suggested that nuclei in hydrodynamical equilibrium may obtain toroidal and/or spherical bubble topologies. The possiblilites of such shapes have been extensively studied both theoretically and experimentally, see, e.g., Refs. [7]}, [8]}, [9]}, [10]} and references therein. The high degree of symmetries in such nuclei may reduce effectively the dimensionality of the nucleons contained in them.
Moreover, the production of particle jets from the participant region in a specific direction may effectively create an approximately 1D sub-system and in the meanwhile the collective
flow in the reaction plane may create approximately a 2D subsystem in intermediate-relativistic energy heavy-ion reactions [2]}. Similarly, neutron star mergers may create \(\gamma \) -ray bursts
or other particles preferentially in certain directions [12]}, [13]}, [14]}. Moreover, it is well known that the dimensionality plays an important role in simulating neutrino-induced supernova explosions [15]}, [16]}, [17]}, [18]}, [19]}.
Consider for example the crust in neutron stars, its thickness could be roughly estimated to be about \(t\approx 1\,\mathrm {km}\) . Compared with the typical radius of a neutron star with \(R\approx 10\,\mathrm {km}\) , one sees that \(t/4\pi R^2\approx 10^{-3}\ll 1\) . In this case, one may ask if the crust can effectively be treated as a quasi 2D object. Furthermore, given an EOS the core structure of a non-rotating neutron star is determined uniquely by the well-known Tolman-Oppenheimer-Volkoff (TOV) equation depending on the radial coordinate only. Can the core of the neutron star be described effectively as a 1D system?
If we can, then the relevant EOSs for the crust and core should be those with reduced dimensions (relative to the conventional 3D forms). The EOS of asymmetric nucleonic matter (ANM) is among the most important quantities for understanding all properties of neutron stars, such as their thermodynamic features and the transport characteristics [6]}, [21]}, [22]}.
The questions mentioned above naturally call for investigating the nuclear physical quantities (including the EOS of ANM) in a general dimension \(d\)  and to explore their possibly new features with respect to the conventional 3D space.
